RSS feed corrupted?

I know there's been a lot of posts on this issue, but none seems to be my
problem exactly. I've got Windows Vista Home Premium and Office 2007. One
of my RSS feeds has stopped updating both in Outlook and in my Sidebar RSS
feed gadget. (presumably because they use the same common feed.) This feed
updates in IE7 (shows the most recent feeds) and will load in Firefox
bookmarks as well. Other feeds update in both programs, just not the one.
I've tried deleting the feed and resubscribing, but that hasn't solved the
problem (from Local/Microsoft/Feeds). Can there be a problem with the site
the feed is coming from? If not, any other thoughts on how to solve this?
It's driving me nuts.